Sunday 13 October 2013

Bird excrement; the most damaging environmental pollutants

 Bird excrement surface etching


                                            Bird excrement etching (highly magnified)


Bird Excrement Consists of [: Uric acid, C5H4N4O3 [a diprotic acid, thus in strong alkali at high pH it forms the dually charged full urate ion, but at biological pH or in the presence of carbonic acid or carbonate ions it forms the singly charged hydrogen or acid urate ion as its pKa2 is greater than the pKa1 of carbonic acid] [1] 

Water solubility of uric acid and its alkali metal and alkaline earth salts is rather low 
 [: the property of a solid, liquid, or gaseous chemical substance called solute to dissolve in a solid, liquid, or gaseous solvent to form a homogeneous solution of the solute in the solvent]

Cause - the different types of food ingested by birds affect the composition and quantity of droppings. Chemical aggression on the paint surface is caused by strong organic acids acting for an extended period and exposed to high temperatures and moisture (reactivity).

One of the most serious threats to a paint surface; it's not only disgusting - it's a toxic hazard. Bird excrement contains unpleasant fungi, including Histoplasma capsulatum and Cryptococcus neoformans as well as bacteria, including Chlamydophila psittaci. Migratory birds, especially seagulls are known to spread hard-to-treat infections as they can carry antibiotic-resistant bacteria.

These are known to cause pneumonias as well as systemic infections. Various forms of encephalitis are also associated with bird droppings, so avoid direct skin contact.

Unlike mammals, birds don't urinate; their kidneys extract nitrogenous wastes from the bloodstream, but instead of excreting it as urea dissolved in urine, they excrete it in the form of uric acid. Uric acid, being nearly water insoluble, exits a bird's body in the form of crystals that look like a white paste. That's what those streaks of white paint-like substances are that you so often see on the sides of buildings and splattered on vehicle surfaces, which  if left on the surface and is then subjected to reactivity it will result in an indentation in the surface (etching) around the periphery

Bird excrement is one of the most damaging environmental pollutants as they relate to automobile paint as it comprises; Ammonia and urine as white crystals of uric acid (pH 3.0 - 4.5) a small organic compound, which is produced by the breakdown of protein during digestion, and is excreted by reptiles and birds. Uric acid is also the end product of nitrogen catabolism in birds Ammonia is a mixture of nitrogen gas and hydrogen gas; with moisture as a catalyst it becomes Ammonium Hydroxide, which is caustic.

Reactivity

[: acceleration of a chemical reaction by a catalyst]

Be cognizant that an acid is inert until it comes into contact with moisture; any chemical attacking a surface, temperature will dictate reactivity (acceleration of a chemical reaction by a catalyst [moisture and heat]. The more heat and moisture that is present (in the form of high humidity, dew and etc) the more aggressive the acid becomes.

Then you have; an acid + water +oxygen + ozone all of which forms an acidic oxygen molecule that causes a concave indentation (acid etching) to the paint surface it should be noted that until this acid is neutralised subsequent moisture and heat will reactivate the acid and allow further damage, as acid requires an alkaline to neutralize it

 This will cause surface etching (an indentation of the clear coat) so they should be removed without delay. In this case, paint care not only serves aesthetics, but also helps preserve the vehicles.  At lower temperatures (> 40.oF or less) there’s no reactivity and therefore little or no etching.

As urethane clear coat paint is heated by ultra violet radiation, it both softens and expands that same heat dries and solidifies the bird excrement on the paint surface. Once the paint protection product fractures (reaches its melting point) it is no longer able to withstand the acids, which allows them to quickly penetrate the paint matrix.

This will cause surface etching, so they should be removed without delay. In this case, paint care not only serves aesthetics, but also helps preserve the vehicles. The longer the excrement remains on the paint surface, and the higher the temperatures, the harder the dried deposit will be, and the greater the propensity for paint surface damage

At lower temperatures (> 40.oF or less) there’s no reactivity and therefore little or no surface etching

Catalyzed hydrolytic degradation

Definition [: the damage can range from paint discoloration to the film dissolving completely. Bubbling, swelling and etching are typical phenomena]

Be cognizant that there are no polymers or waxes that are acid-proof; they all only offer short-term resistance. The most pertinent factor is to have a layer of (sacrificial) protection between the acid and your paint surface. The second is to ensure that is removed and any residue is neutralized as soon as possible. For added protection apply an organic wax over the polymer sealant, as this acts as a sacrificial barrier and by washing the vehicles paint surface plus the reapplication of the sacrificial barrier on a regular basis.

Paint protection
Most natural contaminants are hydrophilic in nature including bird poop. Automotive clear coats are generally based on urethanes, acrylics, melamine’s, silanes, etc. which are hydrophobic and repel water and other contaminants initially. However as the paint surface gets oxidized environmental contaminants will bond to the surface. Polishing the paint surface removes the oxidized layer and makes the paint surface hydrophobic again for a short period of time.

Waxes (Carnauba and synthetic) as well as polymer sealants might not offer much protection against bird droppings, they will make the surface hydrophobic and minimize bonding of the contaminants to paint. This can help reduce the damage from bird poop and make removal of the contaminants much easier. Besides being very acidic, bird droppings contain enzymes which can break down C-C linkages in automotive paint (See also this article “.Nanotechnology and other Coatings”)

Note: some of the newer coating products rely on a configuration Si-C (SiO2) bond, which are far more resistant to enzymes than the C-C (copolymer) configuration used in polymer sealants. Due to the applied coating thickness they are more resistant to the acids found in excrement than a polymer sealant. Notwithstanding, these acids should be removed as soon as possible.  However, if there is any staining left behind, do not polish it, as this will remove the coating, since the stains are not a sign of etching and usually they are on top of Opti-Coat and can break down/disappear after a few days.

Food Sources

Their main food source in summer is mostly insects and seeds, in the winter/ spring it’s berries, which are very acidic, and if left for any length of time the will cause the porous clear coat to occlude (a non-transparent ‘clouded’ area) or may cause etching (a depression in the paint or glass surfaces)
Birds use gravel to help digest their food, predatory birds (owls, hawks, etc hunt and kill mice and small animals, so ground light weight bone fragments, sand and grit are some of the major components, which can cause scratching.

Excrement removal

Avoid using a quick detailer (QD) spray or a sealant to flush residue, as they usually contain either carnauba wax or polymers, which will seal in the acid and not allow it to dissipate.

Take your time and be careful with its removal, these acids should be removed as quickly as possible. If the affected paintwork is not neutralized any remaining acid residue will be reactivated by moisture and heat.
          Limonene (citrus-based) cleaner (P21S Total Auto Wash) will both emulsify and neutralize the acid or use an alkaline rinse of baking soda and water as soon as is practical is highly recommended.
          1:1 solution Isopropyl alcohol (IPA) and distilled water. The alcohol content acts as a drying agent, which will extract the acid, then thoroughly flush with water to rinse away any grit or sand, etc or use detailers clay to encapsulate it, re-spray the area let it react for 2-3 minutes and wipe dry.
          Glass cleaner (do not use one that contains ammonia; as it acts as an acid accelerant
          Gel alcohol hand cleaner (Purell ®) Place a small amount on to a first aid gauze pad and apply to effected area this will help it stay in place during the necessary react time. The alcohol content acts as a drying agent, which will extract the acid, then thoroughly flush with water to rinse away any grit or sand, etc or use detailers clay to encapsulate it, re-spray the area let it react for 2-3 minutes and wipe dry.

An automobile paint system is porous; when you add moisture and heat to an acidic substance it will erode the paint system very quickly; as the heat opens microscopic fissures in the clear coat allowing ingress, the water provides a carrier system for the acid, and heat acts as a catalyst (reactivity) each time water is reintroduced the acid will be reactivated and erode the paint matrix

Type of Surface Damage

Identify the type of damage (Type I Surface staining or Type II Surface etching (a concave indentation) Ultra violet (UV) radiation (heat) causes the urethane clear coat to expand allowing contaminates to permeate; the same heat greatly accelerates the corrosive abilities (reactivity) of the acid, for these reasons any acid or alkali should be neutralized (See Acid / Alkali Neutralization)

Verification of the type of surface condition can be diagnosed through the use of a 30X magnifier. Any acid should be removed from the paint surface ASAP; proceed by using the least abrasive products first

Type I [is an off-white non-transparent ‘clouded’ stain] that if left for any length of time that will cause the porous clear coat to occlude (become non-transparent) this is usually inherent with a light surface stain.

The paint will usually become stained as soon as the excrement has dried. Providing it is removed quickly and hasn't been subjected to reactivity (moisture and heat) this can usually be removed easily, especially if there is a sacrificial coat of wax on the paint

1.      Use a chemical paint surface cleaner (Z-PC Fusion Dual Action Paint Cleaner) to remove surface stains
2.      Use ValuGuard Acid Neutraliser (Step I) - diluted 1:8 neutralizes acids deposited on the paint surface and in the pores of the paint

3.      Try to dissolve the surface/etched deposits trying one or more of the following;

a)      Use a 2:1 or stronger solution of distilled water/distilled white vinegar (Acetic acid)
b)      Try a 2:1 solution of distilled water/Isopropyl Alcohol (adjust ratio as required)
c)      Or equal parts distilled water/distilled white vinegar/Isopropyl alcohol.

4.      Clean the effected surface with Klasse All-In-One or Zaino Z-PC Fusion Dual Action Paint Cleaner

Type II [is a mark with surface etching (a concave indentation) around its perimeter] this is usually the result of a stain that has been on the surface for a while and has been subjected to reactivity (the addition of moisture and heat), which produces an acid that etches the paint surface. After the excrement has dried the acid will begin to corrode the paint surface, this corrosion accelerates once moisture and heat (reactivity) is added, it may take minutes or up to an hour for it to etch the paint surface

1.      Use a chemical paint surface cleaner (Z-PC Fusion Dual Action Paint Cleaner) to remove surface stains
2.      Use ValuGuard Acid Neutraliser (Step I) - diluted 1:8 neutralizes acids deposited on the paint surface and in the pores of the paint

3.      Use detailing clay to remove any `hard' surface granules
4.      Use a machine polish (Optimum Polish or Optimum Compound) and a cutting (LC White, Orange or Yellow) foam pad (speed # 4- 5.0) to level the surface

5.      For PPG CeramiClear™ Clear Coat or other hard clear coats substitute Menzerna for machine polish; PO 203 S - Power Finish

6.      Use the least aggressive polish/foam pad first, if this doesn’t remove the problem step-up to a more aggressive polish / foam pad set-up
7.      Wet-sand with 2000, 2500 or 3000 grit finishing paper and polish with a finishing polish
8.      Apply a paint protection

Do not scrub hardened/dried excrement residue, birds use gravel to help digest their food so grit and sand are some of the major components, which can cause scratching as it is very abrasive and will scratch the paint surface. Once it softened (re-liquefied) it enables their removal with less likelihood of damage to the paint surface Do not use on a hot paint surface (soon after driving) as this will cause streaking
Use a solution of Optimum no-rinse (ONR) diluted 1:20 / distilled water in a fine mist spray bottle) and allow to react time as this will soften debris and allow it to be removed with a mesh covered bug sponge

Protection

Klasse, Jeff Werkstatt or Duragloss #105 Total Performance Polish are all acid-based, acrylic polymer or polyethylene-acrylic o they are more resistant to acidic pollutants (acid rain, bird excrement, and etc) there is no product wax, polymer or nano coating, including CeramiClear that is acid-proof. For added protection apply an organic wax over the polymer sealant as this sacrificial barrier and by washing the vehicles paint surface on a regular basis.

Optimum Opti-Coat™ is based on a resin pre-polymer that uses a configuration of (Si 14) (SiO2 -silica) bond, which are far more resistant to enzymes than the C-C configuration used in polymer sealants. As a consequent it is more resistant to the acids found in bird excrement. It forms ceramic bonds at very high temperatures and will not be damaged by extreme heat and therefore resists oxidation.

Opti-Coat has better resistance to chemicals (acid), scratches and release properties than other automotive coating currently in use. This coating  has a 2-4 µ (microns) applied thickness and a hardness of 9H (Pencil Hardness) when fully cross-linked and provides a semi-permanent coating like a regular clear coat lasts indefinitely unless it is removed by polishing, sanding, or paint

Far beyond washing, cleaning and detailing your automobile inside and out, the best preservative action you can take is to cover the car with a car cover. It provides the best protection against industrial fallout (IFO) dust, dirt; ultra violet (UV) and infrared (IR) radiation; bird excrement and windblown debris (See also Car Cover Section)

Aves bomb First Aid Kit- use a 1:20 Optimum No-Rinse (ONR) / distilled water solution in a fine mist spray bottle. The surfactants it contains encapsulate and trap bird and insect excrement, dry surface dust, or light dirt particles making them virtually non-abrasive and it can be used without causing scratches (check contents periodically as heat will evaporate the contents if stored in the car’s trunk)..
Apply with a long nap micro fibre towel using very little surface pressure, dusting with long strokes in one direction only. For stubborn stains, soak the micro fibre towel and allow it to remain in n place for a few minutes and then wipe away the debris.

Caution - Dispose of any towels or wipes used to remove bird droppings immediately and thoroughly wash your hands, as bird lime can harbour diseases

Avoid using a QD spray to flush residue, as they contain either carnauba wax or polymer sealants, which will seal the acid and not allow it to dissipate. Using an alkaline rinse of baking soda and water (to neutralize the acid) as soon as is practical is highly recommended, if the affected paintwork is not neutralized any remaining acid residue will be reactivated (heat and moisture). If the paint or glass surface has been etched the surface can be levelled with a suitable polish (Zaino PC Fusion Dual Action Paint Cleanser) and then apply a paint protection.

Excrement Removal

Be cognizant that the longer the deposit remains on the bodywork and the higher the ambient temperatures, the harder the dried deposit will be, and the greater the propensity for paint damage. This type of damage can only be prevented by motorists remaining vigilant and removing the deposit as this pollutant can have a serious negative impact on your paint finish if not removed safely and expediently. Also be aware there are no polymers, nanotechnology coatings or waxes that are acid-proof; they all only offer short-term resistance although they will make them easier to remove

Use the least abrasive product first-
1.      Use a paint surface cleaner (Z-PC Fusion Dual Action Paint Cleaner)
2.      Try to dissolve the alkaline-based, surface/etched mineral water deposits try one or more of the following;

a)      Use a 2:1 or stronger solution of distilled water/distilled white vinegar (Acetic acid)
b)      Try a 2:1 solution of distilled water/Isopropyl Alcohol (adjust ratio as required)
c)      Or equal parts distilled water/distilled white vinegar/Isopropyl alcohol.

3.      Clean the effected surface with Klasse All-In-One or Zaino Z-PC Fusion Dual Action Paint Cleaner
4.      Use detailing clay to remove any 'hard' surface granules

5.      Use a machine polish (Optimum Polish or  Compound) and a cutting (LC White, Orange or Yellow) foam pad (speed # 4- 5.0) to level the surface

6.      For CeramiClear or other hard clear coats substitute Menzerna for machine polish; Super Intensive Polish / Nano Polish (105FF) or Final Finish Polish (106FA)
7.      Use the least aggressive polish/foam pad first, if this doesn’t remove the problem step-up to a more aggressive polish / foam pad set-up
8.      Wet-sand with 2000, 2500 or 3000 grit finishing paper

Bibliography

1.                  Alma Heritage Science – Uric acid from bird droppings
2.                  Effects of Environmental Conditions on Degradation of Automotive Coatings, a paper by Mohsen Mohseni, Bahram Ramezanzadeh and Hossain Yari
3.                  Bond Disassociation Energies in Organosilicon Compounds, a paper by Robin Walsh
4.                  Polymer Basics DoITPoMS - University of Cambridge

Relevant Articles

1.      “Acid / Alkali Neutralization” - http://www.autopia.org/forum/autopia-detailing-wiki/140032-acid-base-alkali-neutralization.html#post1489787
2.      “Detailer’s Clay” - http://www.autopia.org/forum/autopia-detailing-wiki/137637-detailers-clay.html#post1459468
3.      “Environmental Damage” - http://www.autopia.org/forum/car-detailing/136393-environmental-damage.html#
6.       “What will decontamination remove that washing / clay will not? “ - http://www.autopia.org/forum/guide-detailing/136545-what-will-decontamination-remove-washing-will-not.html
7.      “Why use a wax on top of a polymer sealant?” - http://www.autopia.org/forum/autopia-detailing-wiki/136406-why-use-wax-top-polymer-sealant.html



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